Rising Sea Level Rising Sea Level Rising sea levels have been disturbing geographers and geologists for some time now. Scientists are constantly trying to prevent the effects rising waters are causing, which mainly includes beach and island erosion. So far, their attempts with man-made development on beaches along the eastern coast of America have only made things worse.
“Up and down the U.S. coast, public money is subsidizing private property on islands made of sand, the stuff on which, as the Bible says, only fools build” (Ackerman 7). In recent years there has been a trend towards living on the barrier islands of America’s Atlantic Coast. High rise condominiums, numerous shops, and several businesses have been built to sustain large populations on these islands and continue to be built.
As a result, this vital chain of islands that lies between the ocean and the mainland are at risk. While interfering with the natural configuration of these islands, human construction has advanced the rate of beach erosion, thus leaving the mainland with no barriers during times of high surf. This effect has also led to costly, unnatural ways to preserve the barrier islands. Saving these islands in their natural state by curbing human encroachment will both protect mainland populations from high surf and save a considerable amount of federal money.
The barrier islands are a chain of islands, stretching from New York to southern Texas, that have served as a critical barrier from the Atlantic Ocean for well over the past 4,500 years (Ackerman 23). These islands however are not as stable as those who live on them would like it to be. Beaches, and in fact whole islands, are constantly eroded as they are subjected to varying winds, currents and changing sea levels. Along Florida’s East Coast, roughly 368 miles, the average shoreline change is retreating 22cm per year. Under natural conditions, native vegetation and shifting sands constantly replace or withhold sand on the islands (16). Unfortunately for the inhabitants of the barrier islands, this is a geological behavior which can only continue if the islands remain in a natural state.
In recent years humans on these shorelines and islands have been responding to the naturally changing conditions, through the use of man made structures such as seawalls, groins, and sand replenishment, in an effort to save beachfront property from erosion. Obstructing the natural shifts of the islands, says Orrin Pilkey of Duke University who has studied these islands for thirty years, will cause them to, “be lost forever” (16-17). Attempting to hold beaches in place with the use of seawalls, groins, and sand replenishment may seem like a good solution in theory, but in practice they probe ineffective. One of the most common methods of attempting to hold barrier island beaches in place is through the use of sea walls, which are costly and ineffective. Seawalls are typically cement walls constructed parallel to the seashore in an effort to block waves from coming over the beach and into property.
However, seawalls tend to withhold sand behind the wall during times of high surf and the natural tendency of the beach to respond to waves is disturbed (Kaufman 207). The structures commonly fail from undermining or erosion by waves breaking over their tops. Under normal conditions sand would be spread out by outgoing currents, which in turn would lower the slope of the beach and cause the waves to break gradually. With seawalls in place, sand remains stationary while waves erode the beach as wave energy is deflected against sand not protected by the seawall (208).
In addition to advancing the erosion rate of the sand and inhibiting the beaches’ natural tendencies, seawalls have become quite costly to maintain. For example, in New York $120 million was paid by the federal government to sustain and replenish seawall installations as of 1996, and repairs continue to be made (Dixon 231). Clearly, this method is both costly and ineffective. Another commonly used method of stopping erosion is the placement of groins, which are also ineffective.
Groins are pilings of rocks that extend into the ocean and perpendicular to the shore. Like seawalls, the primary purpose of a groin is to trap sand, but in longshore currents rather than sand deposits already on the beach. Contrary to their intended purpose, these structures trap sand on the side facing a longshore current and leave the opposite side without sand (Kaufman 207). Over time, the side not facing longshore currents erodes and the initial problem reoccurs. Once again, after the unsuccessful use of groins, money and resources must be spent to restore the beach. A recent method of stopping erosion, and perhaps the most expensive, is that of sand replenishment.
Sand replenishment uses dredging techniques to pipe sand from offshore deposits to the beach in an attempt to replace sand. This operation is also costly and the sand is usually lost in a major storm. Renourished beaches have a shorter life due to compaction and sea bottom imbalance differences. One example of its cost is that of Sea Bright beach where, at one million dollars a square mile; their beach was replenished (Ackerman 29).
The total cost of this operation, which lasted between 1994 and 1996, was $36 million (29). These are just a few of the myriad of inadequate attempts to stop seashore erosion. Not only do these human obstructions to the natural course of nature cause an accelerated erosion, millions of government dollars are being lost in the process of attempting to save beach front property from natural erosion. There are over 90 Federal navigation projects and 21 Federal shore protection projects in Florida alone. These projects have an annual maintenance cost of $32 million.
Stephen Leatherman, head of the Coastal Research laboratory at the University of Maryland, suggests that, “In [coastal] nourishment projects locals pitch in about 5 percent, state and county tax payers pay about 30 percent, and the federal government pays the rest” (Ackerman 30). Apparently, at the cost of the American government, large sums of money are being spent on these futile efforts to stop natural occurrences. Recently in the past few years, a new attribute has been looked at. A bulge formed by Ice Age glaciers is slowly settling, while the mid-Atlantic coast is falling.
In many places, the sea is taking back the land at the rate of about an inch every 25 years. Originally, scientists pondered why the sea level was rising faster between Florida and New York than farther north. They hypothesized that it must have been a shift in the Gulf Stream, but this new research showing the fall of the land proved them wrong. Regardless, sea levels continue to rise and scientists are running out of ideas to prevent this from happening. Global sea level has risen 4 to 10 inches during the past 100 years because of global warming.
By year 2050, a 16-inch sea-level rise is projected. Consequences of a higher sea-level to our coastal areas have not only included erosion, but some believe other effects it will have will include: tourism, the availability of drinking water, and damage from storms. The only effective solution that seems practical at the moment, without risking such large sums of money, is that human occupations of these islands become restricted. In most cases, people probably come to the seashore for recreation and rarely for necessity. Why not just live minutes away on the mainland and avoid having millions of dollars being spent on keeping beachfront property from washing away? This way federal money currently being spent on coastal projects, such as seawalls, groins and sand replenishment, can be allocated to more pressing problems of our nation. Until another economical solution, which does not contribute to the problem of erosion, is possible people should minimize residential development on the barrier islands before both the beaches and money wash away.
Bibliography Ackerman, Jennifer. “Islands at the Edge.” National Geographic. August, 1997:2-31. Dean, G. Robert M.D.
“Review of Long-Term Shoreline Changes in Florida” Online. AOL. http://bigfoot.wes.army.mil/6727.html Dixon, Katherine L., and Orrin H. Pilkey. The Corps and the shore. Washington, D.C: Island Press, 1996.
Head, M. Clarence and Marcus, B. Robert. The Face of Florida. Kendall/Hunt Publishing Company 1998:144-147 Kaufman, Wallace, and Orrin H.
Pilkey. The beaches are moving: the drowning of America’s shoreline. New York: Anchor Press, 1979.
